Transfer mechanism for a continuous heat transfer system

ABSTRACT

A transfer mechanism for use in a continuous cooking system includes a non-metallic counter-balance having a contact bar located toward its uppermost end and a load located toward its lowermost end. The contact bar is sized to span a useable width of the belt and the load is sized to urge the contact bar into continued contact with a portion of the belt as the belt travels around the end roller. Means such as a rotational joint is provided for pivoting the counter-balance toward and away from belt, the joint being arranged to provide a predetermined amount of travel relative to the belt. Means such as a slot is provided for adjusting a position of the counter-balance relative to the belt. The uppermost product-contact surface of the bar can be round, flat, or angled and can include grooves to reduce the amount of contact area.

BACKGROUND OF THE INVENTION

This invention relates generally to continuous heat transfer systems ofthe kind used in commercial settings to produce pre-cooked foodproducts. More particularly, the invention relates to transfermechanisms and devices used to transfer food product into and out ofthese continuous heat transfer systems such as fryers, water cookers,steamers, microwave, infrared systems, and linear and spiral ovens.

The development of continuous ovens in the food industry has grownsignificantly over the past 20 years, along with the increased demandfor pre-cooked food products and the range of those products. Productsranging from roasted vegetables to teriyaki chicken and other marinatedchicken products are now cooked on continuous ovens and an increasingnumber of food products are cooked in continuous fryers, water cookers,steamers, microwave, and infrared systems. Practically every heattransfer system now known to man is utilized on food products.

A constant challenge for the manufacturers of this equipment is thetransfers into and out of the continuous heat transfer system. By way ofexample, consider the transfer of a partially cooked sausage patty beingtransferred off the end of a spiral oven cook belt in a first (par-cook)zone and transferred in-line to a second spiral oven to be fully cooked.Those skilled in the art would recognize that the transfer mechanismused in a spiral oven application can apply to any continuous heattransfer system or process.

The patties are nominally 3/16″ thick and 3¾″ in diameter, weighing 1.3oz. When in batter form, the sausage must be formed into patties at atemperature of 25° F. to 28° F. Forming the patties below the freezingpoint greatly aids in the transfer of the product into the spiral oven.Above this temperature, the batter is more fluid and will not form witha consistent shape. Like any meat product, the more each patty iscooked, the more the protein sets up and the more rigid the productbecomes. Therefore, fully cooking the patties helps the product transfermore easily but, like par-cooked product, fully cooked product can alsoadhere to the belt.

Some spiral oven manufacturers, such as GEA and Marel, seek to overcomethis problem by having one belt that passes through two spirals,effectively eliminating the transfer between the first and second zones.However, this solution restricts the residence time in each zone to afixed formula. For example, if Zone 1 has 100 meters of belt and Zone 2has 100 meters of belt, the residence time in each zone must be equal.Similarly, if the belt ratio in each zone is different, for example 70to 30, then the overall time is fixed to a 70/30 split.

Residence time in each zone can independently vary by using a transfersystem like one provided by Unitherm Food Systems, Inc. (“Unitherm”)which allows each zone to have a separate belt. The Unitherm system usesa driven roller located at the end of the heat transfer equipment, witha small gap between the belt and the roller. The gap eliminatesmetal-to-metal contact that can create metal shavings or oxidation thatdevelops a black oil-like substance that emulsifies between the metalsurfaces. The reliability of this transfer system is critical because ifit fails on any part of the belt, product can be ruined during thetransfer (or failed transfer) and not recovered.

Other Unitherm transfer systems include a close, tight-turn radiusshafts with belts. Again, there is a small gap between the belt and theshafts. Occasionally a fixed scraper is used that is in contact with thebelt. This type of transfer, while effective, can wear out quickly andcan occasionally jam against the belt.

Because spiral oven belts expand and contract—collapsing on the insideand, in some configurations, expanding on the outside—the belts can formtemporary bumps, or peaks and valleys, when the links do not rest asintended or as the belt links travel around the curvature of a shaft.The rate of expansion and contraction at the discharge roller can alsovary.

The belts are typically of the kind made by Ashworth Brothers andCambridge Belt Co. (see FIG. 1 for a typical oven belt pattern). As thebelt turns around the end of the roller/sprocket at the discharge orexit end of the belt, the belt takes a polygonal shape due to thepresence of rigid links, that is, turning in a manner similar torotating a hexagon. Therefore, the radius is not smooth. Additionally,the temperature at this end can be in the range of 200° F. to 450° F.,depending on the operating temperature of the oven. In processes thatmake use of flame grills, the temperature at the exit end of the beltcan be as high as 800° F.

There is a need for a transfer system that can reliably transferpar-cooked meat product and transfer product off the hot, non-smoothradius, end-portion of the belt that is in a variable state of collapseand, potentially, with a temporary bump, peak, or valley in the belt.

SUMMARY OF THE INVENTION

A transfer mechanism made according to this invention includes anon-metallic counter-balance which has a contact bar located toward itsuppermost end and a load located toward its lowermost end. The contactbar is preferably sized to span a useable width of the belt and theload, which can be a physical counterweight, is sized to urge thecontact bar into continued contact with a portion of the belt as thebelt travels around the end roller. Means for pivoting thecounter-balance toward and away from belt, such as a rotational joint,provide a predetermined amount of travel relative to belt. Means foradjusting a position of the counter-balance relative to the belt, suchas an arcuate slot, are also provided.

Preferably, the counter-balance is a thermoplastic capable ofwithstanding a temperature of at least 200° F. The uppermostproduct-contact surface of the contact bar can be cylindrical-shaped,flat or angled, and may include a plurality of grooves arrangedperpendicular to a longitudinal axis of the contact bar. The bar canalso be tapered along its length.

Objectives of the invention include but are not limited to providing atransfer mechanism that (1) does not wear out quickly and oroccasionally jam against the belt; (2) eliminates or reduces the chanceof product adhering to the transfer mechanism during product transfer;(3) can reliably transfer product off the hot, non-smooth radius,end-portion of the belt that is in a variable state of collapse and,potentially, with a temporary bump, peak, or valley in the belt; (4) canremain in constant (no-gap) contact with the belt and (5) can beretrofitted for use in existing continuous cooking systems.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a prior art cook belt.

FIG. 2 is an isometric view of a preferred embodiment of a transfermechanism made according to this invention.

FIG. 3 is a side view of the transfer mechanism of FIG. 2 when installedat the end of an upstream continuous heat transfer process such as aspiral oven and arranged to transfer partially cooked or fully cookedproduct to a belt of an immediate downstream process.

FIG. 4 is a side view of the transfer mechanism of FIG. 2 illustratinghow its position and angle can be changed relative to the belt.

FIG. 5 is an isometric view of the transfer mechanism of FIG. 2 wheninstalled at the end of a continuous heat transfer process.

FIG. 6 is an isometric view of an alternate preferred embodiment of thetransfer mechanism's contact bar. The bar has a triangular profile andincludes grooves along the direction of travel to reduce contact surfacearea. Additionally, the bar has a tapered profile along the width of thebelt to create a varied length of the top product-contact surface toaccommodate belts which have non-uniform characteristics across theirwidth.

FIG. 7 is an isometric view of an another alternate embodiment of thecontact bar. The bar provides a smooth, rounded contact surface to thebelt, but has a flat (angled) top surface to assist in thescraping/peeling of product from the belt rather than allow thin pattiesto ‘nose-dive’ into a rounded top surface.

ELEMENTS AND NUMBERING USED IN THE DRAWINGS

-   -   11 Sprocket-driven belt (“first belt”)    -   13 Sprocket and roller    -   15 End of continuous heat transfer system (e.g. spiral oven)    -   17 Curved or polygonal portion of 11    -   20 Counterbalance    -   21 Contact bar or roller    -   22 Grooves    -   23 Upper end    -   25 Arm or plate    -   26 Top (uppermost) product-contact surface    -   27 Load    -   28 Taper or tapered profile    -   29 Lower end    -   31 Pivot arm or shaft (pivot point or rotational joint)    -   33 Adjustment slot    -   35 Scraper    -   37 Upper surface    -   41 Belt (“second belt”)

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of a transfer mechanism made according to thisinvention includes an inverted counter-balance 20 that is designed to,and can follow, the polygonal pattern of the cook belt 11 as the cookbelt 11 travels the around the sprocket and roller 13 (see FIGS. 2-5).Cook belt 11 is of a kind well known in the art and can be a mesh- orlink-style belt used in any of a number of continuous heat transfersystems commonly used to produce pre-cooked food products (see e.g. FIG.1).

The sprocket and roller 13 is located at the end 15 of a continuous heattransfer system or process such as a fryer, water cooker, steamer,microwave, infrared system, or linear or spiral oven (not shown).Counter-balance 20 assists in the transfer of the product cooked orpar-cooked by the heat transfer system to a belt 41 of the nextimmediate downstream process. Typically, belt 41 is arranged at a lowerelevation than belt 11.

Preferably, the angle and position of the counter-balance 20 isadjustable, as is the load 27 applied on the counter-balance 20. Theload 27, which can be determined through calculation and routineexperimentation, is selected for the specific belt 11, conveyorplacement/angle, speed, and product type of the pre-cooked food productapplication. Adjusting means such as an adjustment slot 33 or itsequivalent allows for the proper conveyor placement/angle of thecounter-balance 20 (see FIG. 4).

The counter-balance 20 includes a contact bar or roller 21 located atthe upper end 23 of the counter-balance arm or plate 25 and a load 27located toward the lower end 29. Contact bar 21 is not limited to around or cylindrical shape (see FIG. 2) but can be any shape preferableand appropriate for the specific application, such as a triangularprofile or containing variation across the belt width. For example, inone preferred embodiment the bar 21 has a triangular profile andincludes grooves 22 along the direction of travel (perpendicular to alongitudinal axis of the bar 21) to reduce contact surface area (seeFIG. 6). Additionally, the bar 21 has a tapered profile 28 along thewidth of the belt 11 to create a varied length of the topproduct-contact surface to accommodate belts 11 which have non-uniformcharacteristics across their width. In another alternate embodiment ofthe contact bar 21, bar 21 includes a smooth, rounded contact surface tothe belt 11, but has a flat (angled) top product-contact surface 26 toassist in the scraping/peeling of product from the belt 11 rather thanallow thin patties to ‘nose-dive’ into a rounded top surface. (see FIG.7).

The load 27, in combination with pivoting means such as a pivot arm orshaft 31, allows the bar 21 to be in constant contact with a curved orpolygonal portion 17 of the belt 11 along a usable width “W” of the belt11 but does not inhibit the speed at which the belt 11 moves around (orabout) the roller 13. If there is an isolated high spot on belt 11, thehigh spot will generally be in a flexible (unsupported region) where theapplied force (if great enough) will press or flatten the high spot inthe flexible portion. Generally, high spots are more specific to thelinear direction of belt travel, either through the previously mentionedrotation of a polygon or through a wire mesh overlay that has thepotential to create a high spot as the belt travels around the shaft.

Pivoting means other than shaft 31 can be used to provide a rotatingjoint. For example, a pin or bolt and bushing combination or a bearingcan be used.

The material used for counter-balance 20 is preferably one that isnon-metallic, low friction, food-grade (FDA-compliant) material that canwithstand, at a minimum, 200° F. and, more preferably, at least 450° F.In other embodiments, the material can withstand temperatures up to 800°F. A suitable material is an engineering thermoplastic such aspolyetheretherketone (“PEEK”) or its equivalent, which is typicallyrated up to 500° F. RULON® 641 PTFE-based resin (Saint-GobainPerformance Plastics Corp., Aurora, Ohio) is another high temperaturefood-grade plastic that is rated up to 550° F. Other suitable materialscan include a food-grade ceramic or its equivalent. Unlike prior arttransfer mechanisms, no gap is required between the contact bar 21 andthe belt 11 because counter-balance 20 is non-metallic.

When the belt 11 forms a temporary bump or peak, the counter-balance 20pivots away but maintains contact with the belt 11. After the bump orpeak passes, the counter-balance 20 pivots toward the belt 11, againmaintaining constant contact with the belt 11. The counter-balance 20provides for travel through a predetermined angle α, and is preferablean angle that prevents the bar 21 or other portions of the transfermechanism from coming into contact with the belt 41 of the downstreamprocess.

A scraper 35 is located on the upper surface 37 of the counter-balance20. The balance 20 also allows the scraper 35 to maintain contact withthe belt 11 but move out of the way when a temporary flaw in the belt 11is encountered. The scraper 35 may have any kind of edge preferable andappropriate to the application. For example, a scraper 35 having asharper edge than the one shown here can be used (yet still be capableof moving out of the way when required).

Load 27 is illustrated as plurality of physical counterweights. However,applying a load to the belt surface can be done with different methodssuch as but not limited to springs and pneumatics. Regardless of themethod used, what is important is that a sufficient load be applied tothe counter-balance 20 so that it maintains contact with the belt 11 asit moves around roller 13 but can move or pivot away—again, maintainingcontact with the belt 11—when a flaw is encountered. By way of anon-limiting example, counterweights of between 24 and 48 lbm wereapplied, which translated to approximately 12 to 25 lbf of contact forcefrom the scraper on the belt. This, in turn, corresponded to between 0.3and 0.7 lbf applied per inch of belt width. The force necessary in anyspecific application is dependent on a number of variables, includingbut not limited to belt type, operating conditions, speed, andscraper/belt configuration.

What is claimed:
 1. A transfer mechanism for use in a continuous cookingsystem which has a first continuous belt that travels around a rollerlocated at an end of the continuous cooking system, the transfermechanism comprising: a non-metallic counter-balance having a contactbar located toward its uppermost end and a load located toward itslowermost end, the contact bar sized to span a useable width of thebelt, the load sized to urge the contact bar into continued contact witha portion of the first continuous belt as the first continuous belttravels around the roller; means for pivoting the counter-balance towardand away from the portion of the first continuous belt, the pivotingmeans arranged to provide a predetermined amount of travel relative tothe first continuous belt; and means for adjusting a position of thecounter-balance relative to the first continuous belt.
 2. A transfermechanism according to claim 1 wherein the load is at least one physicalcounterweight.
 3. A transfer mechanism according to claim 1 wherein themeans for pivoting the counter-balance is a rotational joint.
 4. Atransfer mechanism according to claim 1 wherein the means for adjustingthe position of the counter-balance is an adjustment slot that receivesa rotational joint connected to the counter-balance.
 5. A transfermechanism according to claim 1 further comprising a scraper located on aupper surface of the counter-balance.
 6. A transfer mechanism accordingto claim 1 wherein the counter-balance is a thermoplastic capable ofwithstanding a temperature of at least 200° F.
 7. A transfer mechanismaccording to claim 6 wherein the counter-balance is a thermoplasticcapable of withstanding a temperature up to 450° F.
 8. A transfermechanism according to claim 6 wherein the thermoplastic ispolyetheretherketone.
 9. A transfer mechanism for use in a continuouscooking system which has a first continuous belt that travels around aroller located at an end of the continuous cooking system, the transfermechanism comprising: a non-metallic counter-balance having a contactbar located toward its uppermost end and a load located toward itslowermost end, the load sized to urge the contact bar into continuedcontact with a portion of the first continuous belt as the firstcontinuous belt travels around the roller; the contact bar having anuppermost product-contact surface with a temperature rating of at least200° F.
 10. A transfer mechanism according to claim 9 wherein theuppermost product-contact surface is cylindrical-shaped.
 11. A transfermechanism according to claim 9 wherein the uppermost product-contactsurface is angled.
 12. A transfer mechanism according to claim 9 whereinthe uppermost product-contact surface includes a plurality of groovesarranged perpendicular to a longitudinal axis of the contact bar.
 13. Atransfer mechanism according to claim 9 wherein the uppermostproduct-contact surface is tapered along a length of the contact bar.14. A transfer mechanism according to claim 9 further comprising meansfor pivoting the counter-balance toward and away from a portion of thefirst continuous belt, the pivoting means arranged to provide apredetermined amount of travel relative to the first continuous belt.15. A transfer mechanism according to claim 9 further comprising meansfor adjusting a position of the counter-balance relative to the firstcontinuous belt.